I am analyzing force-time data from a CMJ (100 Hz) in Python to calculate jump height, takeoff velocity, peak force, and RSI_mod. However, I am encountering the following issues:

Jump Phase Detection – The script struggles to accurately detect takeoff and landing using force thresholds (90% BW for takeoff, 110% BW for landing). The identified phases don’t align well with the force-time curve, affecting subsequent calculations.

Takeoff Velocity & Jump Height – Using the impulse-momentum method, takeoff velocity sometimes turns out negative or zero, leading to unrealistic jump heights. The issue may stem from incorrect impulse calculation or force integration.

Peak Force Before Takeoff – The script aims to find the peak force within 200ms before takeoff but sometimes selects an incorrect value, possibly due to improper indexing or filtering artifacts.

I have applied a Butterworth low-pass filter and adjusted thresholds, but the issues persist. How can I:

Improve jump phase detection to correctly identify takeoff and landing?

Ensure accurate takeoff velocity using the impulse-momentum method?

Reliably detect peak force before takeoff?